<?php
/**
 +----------------------------------------------------------
 * 数据加密、解密
 +----------------------------------------------------------
 * @param string   $string     加密、解密字符串
 * @param string   $operation  加密、解密操作符(ENCODE加密、DECODE解密)
 * @param string   $key        密钥
 * @param string   $expiry     过期时间
 +----------------------------------------------------------
 * @return string
 +---------------------------------------------------------- 
 */
function authcode($string, $operation = 'DECODE', $key = '', $expiry = 0){
    $ckey_length = 4;
    $key         = md5($key != '' ? $key : AuthKey);
    $keya        = md5(substr($key, 0, 16));
    $keyb        = md5(substr($key, 16, 16));
    $keyc        = $ckey_length ? ($operation == 'DECODE' ? substr($string, 0, $ckey_length): substr(md5(microtime()), -$ckey_length)) : '';
    $cryptkey    = $keya.md5($keya.$keyc);
    $key_length  = strlen($cryptkey);
    $string = $operation == 'DECODE' ? 
            base64_decode(substr($string, $ckey_length)) 
            : sprintf('%010d', $expiry ? $expiry + time() : 0).substr(md5($string.$keyb), 0, 16).$string;
    $string_length = strlen($string);
    $result = '';
    $box = range(0, 255);

    $rndkey = array();
    for($i = 0; $i <= 255; $i++) {
        $rndkey[$i] = ord($cryptkey[$i % $key_length]);
    }

    for($j = $i = 0; $i < 256; $i++) {
        $j = ($j + $box[$i] + $rndkey[$i]) % 256;
        $tmp = $box[$i];
        $box[$i] = $box[$j];
        $box[$j] = $tmp;
    }

    for($a = $j = $i = 0; $i < $string_length; $i++) {
        $a = ($a + 1) % 256;
        $j = ($j + $box[$a]) % 256;
        $tmp = $box[$a];
        $box[$a] = $box[$j];
        $box[$j] = $tmp;
        $result .= chr(ord($string[$i]) ^ ($box[($box[$a] + $box[$j]) % 256]));
    }

    if($operation == 'DECODE') {
        if((substr($result, 0, 10) == 0 || substr($result, 0, 10) - time() > 0) && substr($result, 10, 16) == substr(md5(substr($result, 26).$keyb), 0, 16)) {
            return substr($result, 26);
        }else{
            return '';
        }
    } else {
        return $keyc.str_replace('=', '', base64_encode($result));
    }
}


/**
 +----------------------------------------------------------
 * 写cookie
 +----------------------------------------------------------
 * @param string   $key    键
 * @param string   $value  数据
 * @param int      $life   生命周期
 +----------------------------------------------------------
 * @return void
 +----------------------------------------------------------    
 */
function addCookie($key, $value = '', $life = 0, $httponly = false){
    if (empty($key)) return ;
    $timestamp = time();
    $key       = CookiePrefix.$key;
    if ($value == '' || $life < 0){
        $value = '';
        $life  = -1;
    }

    $value  = $value == '' ? $value : authcode($value, 'ENCODE');
    $life   = $life > 0 ? $timestamp + $life : ($life < 0 ? $timestamp - 31536000 : 0);
    $path   = $httponly && PHP_VERSION < '5.2.0' ? CookiePath.'; HttpOnly' : CookiePath;
    $secure = $_SERVER['SERVER_PORT'] == 443 ? 1 : 0;
    if (PHP_VERSION < '5.2.0'){
        setcookie($key, $value, $life, $path, CookieDomain, $secure);
    }else{
        setcookie($key, $value, $life, $path, CookieDomain, $secure, $httponly);
    }
}

/**
 +----------------------------------------------------------
 * 读取cookie
 +----------------------------------------------------------
 * @param  string $key 键
 +----------------------------------------------------------
 * @return string
 +----------------------------------------------------------
 */
function getCookie($key){
    $key = CookiePrefix.$key;
    if(isset($_COOKIE[$key]) && $_COOKIE[$key]){
        return authcode($_COOKIE[$key], 'DECODE');
    }else{
        return '';
    }
}


/**
 +----------------------------------------------------------
 * 清除全部cookie
 +----------------------------------------------------------
 * @return void
 +----------------------------------------------------------
 */
function clearCookie(){
    $keys = array();
    $pos  = !CookiePrefix ?  0 : strlen(CookiePrefix);
    foreach($_COOKIE as $key=>$val){
        $keys[] = substr($key, $pos, strlen($key));
    }

    foreach($keys as $key){
        addCookie($key);
    }
}

/**
 +----------------------------------------------------------
 * 删除cookie
 * @param  string $key 键
 +----------------------------------------------------------
 * @return void
 +----------------------------------------------------------
 */
function removeCookie($key){
    addCookie($key);
}
?>